JP7200098B2 - Sedative device - Google Patents

Description

The present invention relates to sedative devices, and more particularly to sedative devices for sedative delivery that are capable of handling volatile gas forms of sedatives.

Volatile anesthetics are powerful agents that have been demonstrated for use in general anesthesia. General anesthesia induces a painless state of unconsciousness throughout the body by administering a volatile or intravenous anesthetic. Administration of volatile anesthetics usually requires an anesthesia machine. The development of anesthesia machines has focused on the need to minimize the consumption of expensive volatile agents in order to reduce costs and minimize the negative environmental impact of waste gases. Anesthesia machines work on the principle of a circulation system that recirculates spent gas through a carbon dioxide absorber and then back to the patient. Therefore, after the initial input, little new anesthetic gas is required to maintain the desired level of anesthesia.

Anesthesia machines require large capital investments and significant ongoing running costs, which can put pressure on hospital budgets. Additionally, modern anesthesia machines require specially trained personnel to ensure that the equipment and carbon dioxide absorbers are set up and working correctly.

To reduce health care costs, more and more patients are undergoing outpatient or ambulatory surgery, i.e., surgery that does not require an overnight stay in a hospital, which is generally private or small. operated by mutual relationships. The high capital costs and technical support required for anesthesia machines are prohibitively expensive for such small operators, thus making it difficult to use volatile anesthetics for such applications.

In the intensive care unit (ICU), mechanically ventilated patients have traditionally been sedated with intravenous drugs to achieve the required level of sedation and pain relief. Many physicians would prefer to use volatile sedatives in the ICU. This is because it has many advantages over the use of intravenous drugs, especially with respect to certain patient conditions. The use of volatile sedatives in the ICU as an alternative sedation method for mechanically ventilated patients has been the subject of clinical research for nearly 30 years. These results indicate that volatile sedatives have many advantages over conventional agents, but the lack of convenient and efficient delivery methods has prevented the use of volatile agents from gaining momentum.

The use of anesthesia machines in the ICU is prohibitively expensive due to high capital costs and the need for specially trained personnel. Additionally, the ventilator components associated with the anesthesia machine do not have adequate functionality for intensive care patients. An alternative to anesthesia machines is an open-flow system that uses large volumes of expensive anesthetics and discharges the waste directly into the atmosphere.

WO 97/14465 discloses a sedation device for delivering sedatives to a patient using an absorbent filter to absorb and desorb the sedatives during use. The device includes a housing for mounting in the airflow path between the ventilator and the patient. A vaporizer disposed within the housing releases the sedative into the airflow delivered through the device between the ventilator and the patient. An absorbent filter is mounted within the housing to absorb excess sedative exhaled by the patient and returns recovered sedative to the airflow when the patient takes the next breath to conserve the analgesic. The filter is movable within the housing during use between a position in which the airflow passes completely through the filter and a position in which the airflow bypasses the filter.

Various other devices for withdrawing sedatives during administration of inhaled sedatives are described in WO97/36628, WO98/20926, WO05/037357, EP0972534. , WO 88/07876 and US Patent Application Publication No. 2009/0050148.

Inserting any device between the patient and the Y-piece of the breathing circuit connected to the ventilator introduces two complications to the patient's breathing: increased dead space and pressure drop across the device. . This device increases the overall volume of air containing carbon dioxide that must be removed with each breathing cycle, called dead space. Any device inserted into the breathing tube increases this dead space and increases the amount of carbon dioxide inhaled by the patient with each breath. If the amount of air inhaled and exhaled by the patient, called the tidal volume, does not sufficiently exceed the dead space, the patient cannot remove enough carbon dioxide from the ventilation circuit, and the concentration of carbon dioxide is reduced to that of the airflow. rises inside and finally rises in the blood. This leads to respiratory and metabolic difficulties. For patients with relatively high tidal volumes, removal of carbon dioxide from such devices usually poses no problem. However, for patients with smaller tidal volumes, such as smaller adults, patients with compromised lung function, and children, adequate removal of carbon dioxide is difficult to achieve without aggressive ventilation. Sometimes. For such patients, it would be desirable to reduce dead space by minimizing the volume of the sedation device. Generally, patients in intensive care units are critically ill and it may always be beneficial to reduce respiratory resistance by reducing dead space.

Simple miniaturization of existing devices does not provide a solution to this problem as it creates an unacceptable pressure drop across the device during use. Even a small pressure drop can make breathing very difficult for some patients. Pressure drop is often greatest when the patient needs peak airflow, ie when the patient needs the most air and the device is the most resistant to airflow. The reflective efficiency of carbon filters can also be reduced, thus requiring more soothing agents, which is undesirable.

The present invention is directed to overcoming these problems.

According to the present invention, a sedative device comprising:
A housing having an internal volume between 30ml and 110ml,
having a ventilator chamber and a coupled juxtaposed vaporizer chamber in communication with the ventilator chamber;
the ventilator chamber has an inlet port for connecting to a ventilator;
a housing having an exit port for connecting the vaporizer chamber to a patient breathing tube;
a filter positioned between the ventilator chamber and the vaporizer chamber, the filter forming a common gas permeable partition between the ventilator chamber and the vaporizer chamber;
A calming device is provided that includes a vaporizer mounted within a vaporizer chamber.

In a particularly preferred embodiment, the inlet port is mounted on a side of the ventilator chamber, positioned to direct air across the surface of the filter within the ventilator chamber, and a deflection ramp mounted within the ventilator chamber. a section is provided, the deflection ramp coupled to and adjacent the inlet port, the deflection ramp extending across and spaced from the inlet port, the deflection ramp angled relative to the inlet port; and flares outwardly from the inlet port, thereby directing incoming air from the inlet port inwardly toward the filter and outwardly from the inlet port over the entire surface of the filter.

In another embodiment, elongated air distribution fins are disposed within the ventilator chamber on the outer wall of the ventilator chamber in alignment with the inlet port at the inner end of the ramp and extending away from the ramp. It is attached.

In another embodiment, the vaporizer chamber has a concave outer wall portion forming an elongated channel in which the vaporizer is mounted, the vaporizer comprises an elongated porous rod, and a vaporizer mounting support within the vaporizer chamber. supports the vaporizer rod within the elongated channel spaced from the concave outer wall portion and aligned with the outlet port of the vaporizer chamber.

In one embodiment of the invention, an air distribution manifold is attached to the inlet port for directing incoming air over the surface of the filter.

In another embodiment, a curved ramp is provided at the outlet of the air distribution manifold to direct incoming air across the filter.

In another embodiment, the inlet port is attached to a side of the ventilator chamber and positioned to direct air across the surface of the filter within the ventilator chamber.

In another embodiment, the outlet port is attached to a side of the vaporizer chamber and the outlet port is arranged to draw air from the entire surface of the filter within the vaporizer chamber.

In another embodiment, the inlet and outlet ports are substantially parallel, i.e., the axes of the inlet and outlet ports are substantially parallel, and the inlet and outlet ports are at opposite ends of the housing. placed.

In another embodiment, the air distribution manifold extends 20% to 35% of the length of the ventilator chamber.

In another embodiment, the air distribution manifold extends about 25% of the length of the ventilator chamber.

In another embodiment, the width of the outlet end of the air distribution manifold is 50% to 75% of the maximum width of the ventilator chamber.

In another embodiment, the width of the outlet end of the air distribution manifold is about 65% of the maximum width of the ventilator chamber.

In another embodiment, the ventilator chamber extends outwardly from the air distribution manifold.

In another embodiment, the vaporizer chamber has a concave or bowl-like profile.

In another embodiment, the vaporizer chamber has a sidewall extending outwardly from the filter with a concave outer wall portion at its outer end.

In another embodiment, the sidewalls taper between the ends of the vaporizer chamber and the outlet port is attached to the wider end of the vaporizer chamber.

In another embodiment, vaporizer mounting supports are provided at both ends of the vaporizer chamber.

In another embodiment, one of the vaporizer mounting supports is attached to the outlet port.

In another embodiment, one or more filter support posts are mounted within the vaporizer chamber and disposed between the mounting supports, the filter support posts projecting outwardly from the concave outer wall portion.

In another embodiment, a filter retaining grill is mounted within the ventilator chamber against a surface of the filter, and at least one spacer element extends outwardly from the outer wall of the ventilator chamber, thereby It engages the grille and urges it against the surface of the filter away from the outer wall.

In another embodiment, the spacer element comprises a plurality of spaced apart spacer posts.

In another embodiment, each spacer post has a sharp leading edge facing the inlet port.

In another embodiment, the air distribution fins have sharp leading edges facing the inlet port.

In another embodiment, the housing is oval. Alternatively, the housing may be oval or circular.

In another embodiment, the inlet port is located at the narrow end of the housing and the outlet port is located at the wide end of the housing.

In another embodiment, the inner surface of the housing is smooth or highly polished.

In another embodiment, the housing has an internal volume of about 50ml.

The invention will be understood more clearly from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings.

1 is a perspective view of a sedation device according to the invention; FIG. 1 is a cross-sectional perspective view of a sedation device; FIG. Fig. 2 is a perspective view of a ventilator chamber housing forming part of the apparatus; Figure 2 is a perspective view of a vaporizer chamber housing forming part of the apparatus; 4 is a cross-sectional view along VV in FIG. 3; FIG. 4 is a cross-sectional view along VI-VI of FIG. 3; FIG. FIG. 5 is a cross-sectional view along VII-VII of FIG. 4; FIG. 5 is a cross-sectional view along VIII-VIII of FIG. 4; Fig. 3 is an elevational view showing the sedation device in use; Fig. 2 is a cross-sectional view of another sedation device according to a second embodiment of the present invention; Fig. 2 is a perspective view of a filter retaining grill for use with the sedation device of the present invention; 1 is a perspective view of a ventilator chamber housing forming part of a sedation apparatus according to the present invention; FIG. 1 is a perspective view of a vaporizer chamber housing forming part of a sedation device according to the present invention; FIG.

Referring first to Figures 1-9, there is shown a sedation device according to the present invention, generally indicated by the reference number 1, for delivery and recirculation of anesthetic agent. The sedation device 1 has a housing 2 with a ventilator chamber 3 and an associated vaporizer chamber 4 within it, which overlap and are mounted between the chambers 3, 4 and a chamber separated by a filter 5 forming a common gas permeable partition between 3,4. An inlet port 7 is provided in the top of the housing 2 at one end of the ventilator chamber 3 for connection, in use, to the patient's ventilator 50 (FIG. 9). The outlet port 8 of the vaporizer chamber 4 can be connected to the patient via a breathing tube 54 . Note that in this case the inlet port 7 and the outlet port 8 are substantially parallel and located at opposite ends of the housing 2 along the longitudinal centerline of the housing 2 . A vaporizer 10 is mounted within the vaporizer chamber 4 for supplying a volatile soothing agent to the vaporizer chamber 4 during use.

The housing 2 has an internal volume of 30ml to 110ml and may conveniently be made of a plastic material and is provided in two parts that snap together: the ventilator chamber housing 12 and the vaporizer chamber housing 13. . The housing 2 is generally oval shaped as best shown in FIGS. 3 and 4, although other shapes such as elliptical or circular may be possible. Note that inlet port 7 is located at the narrow end of housing 2 and outlet port 8 is attached to the wide end of housing 2 .

Referring particularly to FIGS. 2 and 3, an air deflection ramp 18 is mounted within ventilator chamber 3 at inlet port 7 to direct incoming air across upper surface 16 of filter 5 . An air deflection ramp 18 is associated with and mounted adjacent to the inlet port 7 and extends across and is spaced from the inlet port 7 . The air deflection ramps 18 are angled with respect to the inlet port 7 as shown in FIG. , directs incoming air inwardly from the inlet port 7 toward the filter 5 and outwardly from the inlet port 7 across the upper surface 16 of the filter 5 . That is, incoming air delivered from the ventilator through inlet port 7 is directed downwardly and outwardly from inlet port 7 and distributed across upper surface 16 of filter 5 .

This air deflection ramp 18 extends over 20% to 35% of the total length of the ventilator chamber 3 and preferably over about 25% of the length of the ventilator chamber 3 . The width W (FIG. 3) of the outlet end of air deflection ramp 18 is preferably between 50% and 75% of the maximum width of ventilator chamber 3 .

It should also be noted that the air deflection ramps 18 are curved to provide smooth air distribution throughout the ventilator chamber 3 . The air deflection ramps 18 encourage the incoming air to spread and travel across the inner surface of the ventilator chamber 3 . Air is evenly distributed throughout the ventilator chamber 3 and across the upper surface 16 of the filter 5 .

In order to provide a smooth flow of air through the sedation device 1 , the shape of the curved ramp 18 varies according to the interior volume of the housing 2 . Generally, the curvature of ramp 18 is inversely proportional to the internal volume. That is, as the internal volume decreases, the slope curvature becomes more pronounced. Figure 5 shows a ramp 18 of average curvature and also shows a more pronounced ramp curvature 18a for a 40ml volume housing 2 and a shallower ramp curvature 18b for a 110ml volume housing 2. there is

Additionally, the ventilator chamber 3 extends outwardly of the air deflection ramp 18 . The configuration of the air deflection ramps 18 and the shape of the ventilator chamber 3 are such as to promote uniform and smooth delivery of air pumped through the inlet port 7 across the top surface 16 of the filter 5 .

Ventilator chamber housing 12 has a top wall 20 with a downwardly depending peripheral skirt 21 for complementary interengagement with ventilator chamber housing 13 . Appropriate features are provided on the inner surface of the skirt 21 to snap-engage with complementary features on the ventilator chamber housing 13 to separably secure the two chamber housings 12, 13 together. Alternatively, the housing parts 12, 13 can be secured together in other ways, such as gluing or welding.

2 and 4, vaporizer chamber housing 13, also of plastic material, defines an elongated central channel 24 aligned with outlet port 8 of vaporizer chamber 4 in which vaporizer 10 is mounted. It includes a bowl-shaped bottom wall 22 with a concave outer wall portion 23 forming it. An upstanding side wall 26 extends around bottom wall 22 . At the top of sidewall 26, an upstanding peripheral skirt 27 cooperates with the associated skirt 21 on ventilator chamber housing 12 to secure the two housing chambers 12, 13 together. The bottom edge of skirt 21 rests against a laterally projecting flange or lip 28 at the bottom of skirt 27 . Flanges 28 may optionally incorporate valleys for adhesion. Note that sidewall 26 tapers between the ends of vaporizer chamber 4 and outlet port 8 is attached to sidewall 26 at the wide end of vaporizer chamber 4 .

The central channel 24 of the bottom wall 22 forming the floor of the vaporizer chamber 4 is adapted to direct air around the vaporizer 10 which is held apart from the side walls of the central channel 24 by vaporizer mounting supports 30,31. is curved. The recess in the bottom wall 22 is looser and more open in the smaller internal volume, but narrower and sharper in the larger internal volume. FIG. 8 shows a bottom wall 22 of average curvature, a more gradual curvature of the bottom wall 22a of the housing 2 of 40 ml volume and a narrower curvature of the bottom wall 22b of the housing 2 of 110 ml volume.

Vaporizer mounting supports 30, 31 are provided at opposite ends of the vaporizer chamber 4, with a first mounting support 30 attached to the outlet port 8 and a side wall 26 at the opposite end of the vaporizer chamber 4. and a second mounting support 31 attached to the . A pair of spaced apart filter support posts 33 are positioned within channel 24 between mounting supports 30 , 31 projecting outwardly from bottom wall 22 . These filter support posts 33 have a rectangular cross-section or more preferably a circular or oval cross-section aligned with the longitudinal axis of the vaporizer chamber 4 to minimize turbulence in the air flowing through the vaporizer chamber 4 . can have

A sampling port 35 projects radially outwardly of the tube 36 forming the outlet port 8 . In use, it can be connected by a sampling line 37 to a gas monitor 38 (FIG. 9), which measures the concentration of volatile sedative and supplies fresh sedative to the vaporizer chamber 4 via the vaporizer 10. can be used to control the addition of

Vaporizer 10 includes an elongated porous polymer rod extending between mounting supports 30,31. Various other types of vaporizers such as heating elements or vibrating elements can alternatively be provided. A sedative delivery line 40 connects the vaporizer 10 with a syringe or pump to a sedative reservoir 41 (FIG. 9). The sedative from reservoir 41 is vaporized by vaporizer 10 and combines with air within vaporizer chamber 4 before being delivered to the patient through outlet port 8 . Any suitable means such as a syringe or pump or other delivery means may be provided to deliver the sedative substance from reservoir 41 to vaporizer 10 .

Filter 5 comprises an absorbent carbon felt filter bonded or unbonded with antibacterial and antiviral filters. A carbon felt filter can absorb volatile sedatives during exhalation and deliver them during inhalation, thus allowing the sedative to circulate. Carbon felt can reflect exhaled volatile agents at most common ventilator parameters without reflecting clinically significant concentrations of carbon dioxide. Carbon felt also reflects heat and moisture.

Note that filter 5 is substantially parallel to the central axis of inlet port 7 and outlet port 8 so that air entering and exiting sedation device 1 flows across top 16 and bottom 17 surfaces of filter 5 . The activated carbon on filter 5 functions to reflect heat, moisture and volatile sedatives back to the patient. Anti-bacterial and anti-viral filters serve to protect the ventilator circuit from pathogenic contamination.

FIG. 9 shows the sedation device 1 in use mounted between the ventilator 50 and the patient 51 . Inlet port 7 of sedation apparatus 1 connects to ventilator 50 via tubing 52 . Outlet port 8 connects with patient 51 via breathing tube 54 . Fresh air delivered from ventilator 50 enters ventilator chamber 3 through inlet 7 . The incoming air transforms from a narrow tubular airflow delivered through the inlet port 7 to a broad flat airflow that flows smoothly across the ventilator chamber 3 . The air is evenly distributed across the ventilator chamber 3 and across the top surface 16 of the filter 5 . Air flows through filter 5 into vaporizer chamber 4 . Volatile sedatives injected into vaporizer 10 mix with fresh air before exiting vaporizer chamber 4 through outlet port 8 for delivery to patient 51 through breathing tube 54 .

A small sample of air is extracted through sample port 35 for measurement by external gas monitor 38 . The sedative concentration measured by the external gas monitor 38 can be used to report the rate at which new sedative is pumped into the vaporizer chamber 4 to replace the circulated sedative. Air exhaled by the patient 51 and mixed with excess sedative gas re-enters the vaporizer chamber 4 . This air/sedative mixture rises through a filter 5 where the sedative is absorbed and exhaled air is expelled from the device. During the next inhalation, fresh air draws the recovered sedative from filter 5 as it passes through filter 5 from ventilator chamber 3 to vaporizer chamber 4, and with it as the patient breathes. is reused, thereby reflecting and preserving the sedative.

Referring now to FIG. 10, there is shown another sedation device in accordance with the present invention generally indicated by the reference numeral 60. As shown in FIG. It is generally similar to the sedation device previously described, and like parts have been given the same reference numerals. In this case, elongated air distribution fins 61 are mounted within the ventilator chamber 3 on the outside of the ventilator chamber housing 12 or on the inside surface of the top wall 20 . A fin 61 is perpendicular to the top wall 20 and is centrally located on the top wall 20 in alignment with the inlet port 7 at the inner end of the ramp 18 and extends away from the ramp 18 . Fins 61 have sharp leading edges 62 facing inlet port 7 . Fins 61 promote an even distribution of incoming air across surface 16 of filter 5 .

Referring now to Figure 11, there is shown a filter retention grille, generally designated 65, for use with the sedation device of the present invention. The grille 65 has a pair of spaced apart concentric oval rings, an inner ring 66 and an outer ring 67, which have outwardly extending spaced apart arms 69 projecting outwardly of the outer ring 67 along an axis. It is attached to the direction spine 68 . 10, the grill 65 is mounted within the ventilator chamber 3 against the upper surface 16 of the filter 5, with the outer ends 70 and spines 68 of each arm 69 facing the inner surface of the upstanding skirt 27 of the vaporizer chamber 4. to engage. Fins 61 engage central axial spine 68 and force grille 65 against upper surface 16 of filter 5 to maintain an airflow space above filter 5 , i.e., filter 5 outside or above ventilator chamber 3 . Hold away from wall 20 . In this case, the fins 61 therefore also act as spacer elements for the grille 65 . Preferably, a plurality of spaced apart spacer posts project downwardly from the inner surface of the upper wall 20 of the ventilator chamber 3 and engage the inner ring 66 of the grille 65 to hold the filter 5 in place, as described below (FIG. 12). It is kept equally spaced from the top wall 20 .

Referring now to Figure 12, there is shown another ventilator chamber housing 70 according to the present invention. Parts similar to those previously described are provided with the same reference numerals. In this case, the central air distribution fin 61 projects inwardly from the inner surface 71 of the top wall 20 . The leading edge 72 and trailing edge 73 of the air distribution fins are sharp. A plurality of spaced apart spacer posts 75 also project inwardly from the inner surface 71 of the top wall 20 and are arranged in rows on opposite sides of the fins 61 and are engageable with the inner ring 66 of the grille 65 so as to allow the grille 65 to rotate. are equally spaced from the inner surface 71 of the top wall 20 . Each spacer post 75 has a sharp leading edge 76 facing the inlet port 7 and preferably the opposite or trailing edge 77 is also sharp.

FIG. 13 shows another vaporizer chamber housing 80 according to the invention. Parts similar to those previously described are provided with the same reference numerals. In this case, a plurality of spaced apart spacer posts 81 project inwardly from the bottom wall 22 to hold the filter 5 away from the bottom wall 22 . These spacer posts 81 have sharp edges facing the direction of air flow through the vaporizer chamber and are arranged in rows on either side of the central channel 24 .

A second grille 65 is provided for mounting against the lower surface 17 of the filter 5 within the vaporizer chamber 4 to hold the filter 5 away from the bottom wall 22 and by support posts 33 and spacer posts 81 . It is provided to engage and press against the filter 5 .

Advantageously, the sedation device of the present invention has an internal volume ideally between 30 ml and 110 ml, preferably in the range 30 ml to 70 ml, while minimizing pressure drop and changes in sedative reflex efficiency. Works effectively over a range.

In the described embodiment, the inlet and outlet ports are located on opposite sides of the housing, which is the preferred arrangement, although other arrangements of the inlet and outlet ports are possible. Whichever arrangement is used, it is desirable to provide a smooth flow of air over the surface of filter 5 .

Although an oval housing is shown in the example given, other shapes of the housing are possible, for example an oval housing. If an oval housing is used, the inlet port may be provided at either the narrow end or the wide end of the housing, and similarly the outlet port may be provided at either the narrow end or the wide end of the housing. may be placed

Although the filter and inlet and outlet ports are parallel in embodiments, the inlet and/or outlet ports may be angled somewhat if smooth air delivery over the surface of the filter is maintained. .

It will be appreciated that the sedation device according to the present invention provides a device that can be inserted into the ventilator circuit between the patient and the ventilator that can safely and cost effectively deliver volatile sedatives to the patient. . The sedation system of the present invention delivers, stores and reflects volatile sedation agents as efficiently as anesthesia machines, but at a fraction of the cost. The efficiency of the sedation device also means that sedation agent waste is minimal, and any waste generated can be easily directed to an appropriate capture unit. Advantageously, the sedation device of the present invention allows the use of volatile sedation agents in the ICU and other settings at a relatively moderate cost.

It will be appreciated that features of the various embodiments described herein can be combined in sedation devices according to the present invention.

As used herein, the terms "comprise, comprises, comprises, and comprising," or any variation thereof, and "include, includes," The terms "included" and "including", and any variations thereof, are generally considered interchangeable and should all be given the broadest possible interpretation; In the opposite case, the opposite happens.

The invention is not limited to the embodiments described above, which may vary both in construction and in detail within the scope of the appended claims.

Claims (11)

A housing (2) having an internal volume between 30ml and 70ml,
A ventilator chamber housing (12), a vaporizer chamber housing (13) having a ventilator chamber (3) within said ventilator chamber housing (12), and communicating with said ventilator chamber (3). , a juxtaposed vaporizer chamber (4) coupled within said vaporizer chamber housing (13) ;
said ventilator chamber (3) has an inlet port (7) for connecting to a ventilator (50);
said vaporizer chamber (4) has an exit port (8) for connection to a patient breathing tube (54);
a housing (2);
A filter (5) mounted between said ventilator chamber (3) and said vaporizer chamber (4), said filter (5) between said ventilator chamber (3) and said vaporizer chamber (4). a filter (5) forming a gas permeable partition common to
A calming device (1, 60) comprising a vaporizer (10) mounted within said vaporizer chamber (4),
Said inlet port (7) is mounted on a side of said ventilator chamber (3) and arranged to direct air across the surface (16) of said filter (5) within said ventilator chamber (3). provided with an air deflection ramp (18) mounted within said ventilator chamber (3), said deflection ramp (18) being coupled to said inlet port (7) and said inlet port (7) and said deflection ramp (18) is angled with respect to said inlet port (7), thereby diverting incoming air from said inlet port (7) across surface (16) of said filter (5). towards
said air deflection ramp (18) extends between 20% and 35% of the length of said ventilator chamber (3);
Elongated air distribution fins (61) are mounted within said ventilator chamber (3) on the inner surface of the outer wall (20) of said ventilator chamber housing (12), said elongated air distribution fins (61): perpendicular to said outer wall (20) and centrally located in said outer wall (20) in alignment with said inlet port (7) at the inner end of said ramp (18) and said ramp (18); a sedative device (1 , 60) extending away from the . Said vaporizer chamber housing (13) has a bottom wall (22) with a concave outer wall portion forming an elongated channel in which said vaporizer (10) is mounted, said vaporizer (10) being elongated. Vaporizer mounting supports (30, 31) in said vaporizer chamber (4) comprising a porous rod (10) spaced said vaporizer rod (10) in said elongated channel from said concave outer wall portion. 2. A sedation device ( 1, 60) according to claim 1, supported in alignment with said outlet port (8) of said vaporizer chamber (4). Said outlet port (8) is attached to a side wall (26) extending around said bottom wall (22) of said vaporizer chamber housing (13), said outlet port (8) being connected to said vaporizer chamber (4). 3. A sedative device (1, 60) according to claim 1 or 2 , arranged to draw air from across the surface (17) of the filter (5) in the sedation device (1, 60). 4. A device according to any one of claims 1 to 3 , wherein said inlet port (7) and said outlet port (8) are substantially parallel and arranged at opposite ends of said housing (2). Sedative device (1, 60). A sedation device according to any one of the preceding claims, wherein the width of the outlet end of the air deflection ramp (18) is between 50% and 75% of the maximum width of the ventilator chamber (3). (1,60). A sedation device ( 1, 60) according to any preceding claim, wherein said air distribution fin (61) has a sharp front edge (72) facing said inlet port (7). A sedative device (1, 60 ) according to any preceding claim, wherein said housing (2) is oval. A sedation device according to any preceding claim, wherein the housing is oval. A sedation device according to any preceding claim, wherein the housing is circular. A sedation device ( 1 , 60) according to any one of the preceding claims, wherein the inner surface of said housing (2) is smooth. A sedation device ( 1 , 60) according to any one of the preceding claims, wherein said housing (2) has an internal volume of 50 ml.

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